Haemonchus contortus isolates were collected from goats of five locations with different climatic characteristics in Guadeloupe archipelago. They were investigated for morphology, morphometrics and allozyme diversity after passage in immunosuppressed lambs using long acting corticoids. The basic aim of the work was to construct a synthetic strain in laboratory conditions which was representativ...

Three isolates of Haemonchus contortus selected for avermectin resistance in sheep were compared in three in vitro pharmacological tests previously shown to discriminate between field isolates of H. contortus resistant and susceptible to the avermectins. Two isolates, F7-A and IVC, were selected for avermectin resistance in the laboratory from a reference susceptible isolate using suboptimal do...

Water was evaporated from infective Haemonchus contortus larvae suspended in tap, distilled and triple-distilled water, and the nematodes were then exposed to 50% and 75% relative humidity (RH) at 20, 30, 40, and 50 C. Sample groups were rehydrated 4 hr daily in similar quality water, observed for motility, then returned to the same RH and temperature and re-evaporated. This was continued until...

The effects of tannins on adult populations of Haemonchus contortus, Trichostrongylus colubriformis and Teladorsagia circumcincta in goats are characterised mainly by a decrease in egg excretion without any significant changes in worm number. In contrast, the impact of tannins on T. colubriformis or T. circumcincta third-stage larvae (L3) is associated with a significant reduction in worm estab...

Ujumqin sheep are susceptible to infection by the gastrointestinal nematode Haemonchus contortus, which reduces productivity and total meat yield in sheep. Thus, the effects of green tea polyphenol (GTP) supplements (0, 2, 4, or 6g of GTP/kg feed) on dietary nutrient digestibility and meat quality in lambs infected with H. contortus were examined; control lambs were not infected. H. contortus i...

Two field strains of Haemonchus contortus, one from Pretoria on the Highveld and the other from White River in the Lowveld of the Transvaal, showed pronounced resistance to rafoxanide at a dosage rate of 7.5 mg/kg live mass per os. Both of these strains originated from kikuyu pastures under irrigation. Resistance in South Africa to rafoxanide and other anthelmintics, namely, closantel, ivermect...

A group of 12 Merino lambs, 3,5 months of age, which were still suckling, were each dosed with 40 000 infective larvae of Trichostrongylus axei on Day 0. From Day +62-Day 64 each of these lambs and those of a 2nd group of 11 controls were dosed with 30 000 infective larvae of Haemonchus contortus, and all the lambs of both groups were killed on Day +90. Attempts to use T. axei to protect them a...

During a survey of the parasites of antelope in the Bontebok National Park, Swellendam, Cape Province, specimens of Haemonchus contortus with exceptionally long spicules were recovered from 5 out of 8 bontebok, Damaliscus dorcas dorcas, and 3 out of 5 vaal ribbok, Pelea capreolus, but not from 4 springbok, Antidorcas marsupialis. Typically, H. contortus has spicules 0,466 +/- 0,085 mm long, but...

Seven cathepsin B-like cysteine proteases (CBLs) were identified from the immunoprotective excretory-secretory products of Haemonchus contortus. Two-dimensional (2-D) zymography and biotinylated inhibitors were employed to localize active CBLs in 2-D protein gels. Mass spectrometry provided the identification of AC-4, HMCP1, HMCP2, and GCP7 as well as three novel CBLs encoded by clustered expre...

Cholinesterase and acid phosphatase (AP), but not alkaline phosphatase activities, were detected in cytosolic and membrane-bound fractions of ivermectin resistant and susceptible Haemonchus contortus infective-stage larvae. Some differences in acetylcholinesterase activity of cytosolic fractions and in the AP activity of these fractions as well as in the response to AP inhibitors by membrane-bo...